Fra 1994, forskeren Max Zusman. Nevner veldig mange interessante perspektiver på hvordan mekanisk stimuli (percussor, DNM, SI, osv) demper smerte.

http://www.sciencedirect.com/science/article/pii/S0004951414604529

Abstract: The precise source and cause of mechanically evoked sensory and motor responses can sometimes be surprisingly difficult to identify. Accurate interpretation of these responses may be confounded by peripheral as well as central nervous system mechanisms. Examples of such peripheral nervous system mechanisms likely to be of relevance to therapists have been selected from basic and clinical research. Symptomatic relief has been inferred to endorse the diagnostic specificity of mechanical stimulation. The extent to which this would be valid for relief acquired by neurological means is discussed in terms of endogenous pain inhibitory systems

Some degree of local inhibition with mechanical stimuli delivered directly to a pathological site may be mainly a consequence of supplementary input in large diameter cutaneous afferents. Unlike those afferents supplying deep tissue such as joint, muscle etc., small diameter cutaneous afferents appear to be largely impervious to mechanical sensitisation by chemical mediators of the inflammatory response (Handwerker and Reeh 1991).

Therefore, mechanical stimulus parameters which maximise large diameter afferent input from the skin and at the same time minimise sensitised small diameter afferent input from deep tissue such as joint, muscle etc. would be therapeutically effective

Spontaneously occurring clinically relevant symptoms and signs are ultimately a product of both peripheral and central nervous system mechanisms. As  such, they are complexly derived and displayed. Their true origin and significance are sometimes obscure and liable to misinterpretation. Rather than being invariably diagnostically definitive, provocative mechanical manoeuvres can compound these uncertainties. The provocative mechanical manoeuvres used by therapists are, neurologically speaking, relatively crude. They do not have the necessary specificity to always distinguish between pathologically and non pathologically involved tissues and sites, Since their specific systemic effects have not been investigated,  the responses produced with such stimuli are subject to variously influenced and informed interpretation.

The reasons for symptomatic relief produced asa result of these mechanical manoeuvres are not known for certain. Neurologically, this appears to involve inhibitions in the central nervous system. Input conveyed centrally by different classes of primary afferents stimulated at a variety of sites has the potential to produce therapeutically effective inhibitions. Mechanical provocation can confirm the presence of clinically relevant sensory and motor responses. However, understanding what these responses might actually mean in terms of their source and cause would frequently require additional input from the basic sciences.